The present invention relates generally to fluid jet devices. More particularly, the present invention pertains to fluid jet devices, such as ink jet print systems and maintenance modules configured for mounting to an ink jet print system print head.
Fluid jet devices are in wide spread use. One particular use for such a device is in ink jet printers. There are a number of principle types of ink jet printers. One type of printer relies upon capillary action to move a working fluid (e.g., ink) to the print head. The ink is directed from the print head through one or more orifices toward a target substrate. Ink jet printers include an actuator for urging the ink through the orifice. Actuators can include piezzo electric elements, thermal devices and the like. An exemplary ink jet print head is disclosed in DeYoung et al., U.S. Pat. No. 4,418,355.
Typically, the print head includes a fluid passageway or chamber configured for ink flow from a source to the actuator, and through the orifices. During normal operation of the print head, ink is present in the passageway or chamber. Actuation of the actuator draws ink into the passageway through the actuator and out through the orifices. It has, however, been found that air, which can enter the fluid chamber (through the orifices) or dirt or debris that can become lodged in the orifices, results in improper operation of the fluid jet device. Air and debris can result in reduced ink drawn into the flow passageway and subsequently cause the failure to eject ink through the orifices. Thus, it has been found that for effective operation of the print head, the ink flow passageway or chamber must be devoid of air and dirt or debris and that the passageway must remain filled with ink.
A number of devices, configurations and methods have been proposed and are used to prevent improper operation of the print head either by preventing air entrainment in the ink or by preventing debris from gathering at the orifices. Some of these configurations and methods are directed to preventing the entrainment of air and collection of debris, while other configurations and methods are directed to mitigating the effects of air entrainment and debris. Still others are directed to removing air that may have already been entrained in the system, or by removing debris that may have already collected at the orifices.
It has, however, been found that many such “maintenance” designs require complex arrangements of plates, fluid (e.g., air) supplies, vacuum lines and the like external to the print head. Although many of these configurations and methods have been found to be effective, their complexity increases the cost of the overall system, as well as the opportunity for equipment failure because of design and component complexity.
Accordingly, there exists a need for a maintenance module for a fluid jet device having a straight-forward and simple design. Most desirably, such a maintenance module facilitates the collection of purge fluid from the fluid jet device used to entrained air and debris that may have collected on the jet device. Most desirably, such a maintenance module incorporates provisions for drawing a vacuum at the fluid jet device to remove fluid that may have been ejected from the device during the purge cycle.